In the laws of mathematics, especially in rounding off digits, you should take note of the digit following that number no matter how long or short a number is. If the number is preceded by numbers between 0-4, the number does not change. However if its is preceded by numbers between 5-9, add one to the number. In this problem, you are required to round off each number to the nearest ten million before adding them. So 22,471,000 becomes 20,000,000 and 36,730,000 becomes 40,000,000. Add the both of them and you will get 60,000,000. The answer is letter A.